docs: def set_destination(source, suffix, filename=False, ext=None):
      """Create new pdf filename for temp files"""
      source_dirname = os.path.dirname(source)
  
      # Do not create nested temp folders (/temp/temp)
      if not source_dirname.endswith('temp'):
          directory = os.path.join(source_dirname, 'temp')  # directory
      else:
          directory = source_dirname
  
      # Create temp dir if it does not exist
      if not os.path.isdir(directory):
          os.mkdir(directory)
  
      # Parse source filename
      if filename:
          src_file_name = filename
      else:
          src_file_name = Path(source).stem  # file name
      if ext:
          src_file_ext = ext
      else:
          src_file_ext = Path(source).suffix  # file extension
  
      # Concatenate new filename
      dst_path = src_file_name + '_' + suffix + src_file_ext
      full_path = os.path.join(directory, dst_path)  # new full path
  
      if not os.path.exists(full_path):
          return full_path
      else:
          # If file exists, increment number until filename is unique
          number = 1
          while True:
              dst_path = src_file_name + '_' + suffix + '_' + str(number) + src_file_ext
              if not os.path.exists(dst_path):
                  break
              number = number + 1
          full_path = os.path.join(directory, dst_path)  # new full path
          return full_path